Question: Khan.scratchpad.disable(); To move up to the maestro level in his piano school, Kevin needs to master at least $190$ songs. Kevin has already mastered $19$ songs. If Kevin can master $10$ songs per month, what is the minimum number of months it will take him to move to the maestro level?
Solution: To solve this, let's set up an expression to show how many songs Kevin will have mastered after each month. Number of songs mastered $=$ $ $ Months at school $\times$ Songs mastered per month $+$ Songs already mastered Since Kevin Needs to have at least $190$ songs mastered to move to maestro level, we can set up an inequality to find the number of months needed. Number of songs mastered $\geq 190$ Months at school $\times$ Songs mastered per month $ +$ Songs already mastered $\geq 190$ We are solving for the months spent at school, so let the number of months be represented by the variable $x$ We can now plug in: $x \cdot 10 + 19 \geq 190$ $ x \cdot 10 \geq 190 - 19 $ $ x \cdot 10 \geq 171 $ $x \geq \dfrac{171}{10} \approx 17.10$ Since we only care about whole months that Kevin has spent working, we round $17.10$ up to $18$ Kevin must work for at least 18 months.